def equilateral(sides):
    a = sides[0]
    b = sides[1]
    c = sides[2]
    if triangle(sides) and a == b and b == c:
        return True
    return False


def isosceles(sides):
    a = sides[0]
    b = sides[1]
    c = sides[2]
    if triangle(sides) and (a == b or b == c or a == c):
        return True
    return False


def triangle(sides):
    a = sides[0]
    b = sides[1]
    c = sides[2]
    if a > 0 and b > 0 and c > 0 and a + b >= c and b + c >= a and a + c >= b:
        return True
    return False

def scalene(sides):
    return triangle(sides) and not isosceles(sides)